Optical storage properties in cast films of an azopolymer

Neves, Ubaldo Martins das; Santos, David S. dos; Giacometti, J.A.; Zílio, Sérgio Carlos; Misoguti, Lino; Balogh, Débora Terezia; Oliveira, Osvaldo N.; Mendonça, Cleber Renato

doi:10.1590/s1516-14392003000300016

Cited by 7 publications

(4 citation statements)

References 12 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…4,5,[7][8][9]22 In tendons, collagen fibers and their bundles do not follow a strictly parallel path along the tendon axis, but rather show a helical arrangement that obeys the rules of supramolecular chemistry. [12][13][14][15][16] The resulting superstructure is similar to a twisted grain boundary liquid crystal, 13 and the variations in fiber direction in the tissue section are reflected in the absorbances, DR values, and respective standard deviations.…”

Section: Ponceau Ss-collagen Complexes and Liquid Crystalsmentioning

confidence: 99%

“…1,4 Sulfonated dichroic azo-dyes have been used as guest-host molecules in liquid crystals in order to investigate induced birefringence and LD, with a view to applications in optical devices, induced photoalignment, and the study of molecular orientation; the photonic properties of such complexes may also have some applications. [4][5][6][7][8][9] Indeed, the possibility of putting the optical properties of the guest-host effect 6 to practical use in electronic displays has focused interest on the applicability of dyes in nematic liquid crystals. 4 Ponceau SS is a rod-like azo dye with a geometric and chemical structure that meets the conditions for orientation in appropriate liquid crystals and polymers.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Supramolecular order following binding of the dichroic birefringent sulfonic dye Ponceau SS to collagen fibers

Vidal¹,

Mello²

2005

Biopolymers

View full text Add to dashboard Cite

The optical anisotropies (linear dichroism or LD and birefringence) of crystalline aggregates of the sulfonic azo-dye Ponceau SS and of dye complexed with chicken tendon collagen fibers were investigated in order to assess their polarizing properties and similarity to liquid crystals. In some experiments, the staining was preceded by treatment with picric acid. Crystalline fibrous aggregates of the dye had a negative LD, and their electronic transitions were oriented perpendicular to the filamentary structures. The binding of Ponceau SS molecules to the collagen fibers altered the LD signal, with variations in the fiber orientation affecting the resulting dichroic ratios. The long axis of the rod-like dye molecule was assumed to be bound in register, parallel to the collagen fiber. Picric acid did not affect the oriented binding of the azo dye to collagen fibers. There were differences in the optical anisotropy of Ponceau SS-stained tendons from 21-day-old and 41-day-old chickens, indicating that Ponceau SS was able to distinguish between different ordered states of macromolecular aggregation in chicken tendon collagen fibers. In the presence of dichroic rod-like azo-dye molecules such as Ponceau SS, collagen also formed structures with a much higher degree of orientation. The presence of LD in the Ponceau SS-collagen complex even in unpolarized light indicated that this complex can act as a polarizer.

show abstract

Section: Ponceau Ss-collagen Complexes and Liquid Crystalsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Supramolecular order following binding of the dichroic birefringent sulfonic dye Ponceau SS to collagen fibers

Vidal¹,

Mello²

2005

Biopolymers

View full text Add to dashboard Cite

show abstract

“…The photo-induced isomerization process has very interesting potential applications, as e.g. surface relief gratings (SRGs) for holographic storage and optical switching, [7][8][9][10][11][12] in the field of the nanomanipulation of molecules, 13,14 those of the controlled drug delivery 5,6,15 and of the mechano-sensitive channels technology as well. 16 Moreover, due to the azo-groups dipole moment modification as a consequence of the transcis photo-isomerization process, polymers films having photoswitchable wettability can be obtained.…”

Section: Introductionmentioning

confidence: 99%

Surface properties, thermal behavior, and molecular simulations of azo-polysiloxanes under light stimuli. Insight into the relaxation

Resmeriță

Epure

Hurduc³

et al. 2010

Macromol. Res.

View full text Add to dashboard Cite

Light-sensitive materials as azo-polymers have interesting applications in microelectronics, biology, or energy storage, due to their capacity to change their supramolecular ordering. Light-induced modifications result in i) changes in the azobenzene-groups dipole moment due to the trans-cis isomerization, ii) thermal backward cistrans relaxation, and iii) re-ordering of the polymer chain conformation. Conjugation of these phenomena leads to mass transport in the solid state, which is still not well understood. Changes in the surface properties of non-substituted and p-CF 3 ,-CN,-NO 2 -substituted azophenoxy-polysiloxane films, before and after photo-excitation, were examined. Molecular simulations were performed to evaluate the dipole-moments of the trans and cis p-substituted azobenzene groups and provide a general vision of the spatial arrangement of polymer chains. The role of trans-cis back relaxation and that of the polymer matrix relaxation on the surface and bulk of the materials was discussed. Surface free energy determination of the non-substituted azophenoxy-polysiloxane suggested that the relaxation process is dominated by the thermal slow back-isomerization of the cis fraction and not by the motion of a glassy polymer matrix involving both the surface and bulk. A less clear situation was presented by the semi-crystalline polysiloxanes with electron-withdrawing groups substituted in the para-position. This was attributed mainly to the similar values of the dipole-moment of trans and cis azo-group, the former being slightly more dipolar than the latter.

show abstract

“…Light‐induced motions in azobenzene‐containing polymer films1, 2 have attracted much attention because of possible application in micro‐ and nanoscale fabrication, waveguides3 and optical data storage 4–7…”

Section: Introductionmentioning

confidence: 99%

Fabrication of surface‐relief gratings on an azobenzene‐containing epoxy‐based polymer film using atomic force microscopy

Fernández

Zalakain

Ramos

et al. 2010

Polymer International

View full text Add to dashboard Cite

Many studies have been reported on the photo‐fabrication of surface‐relief gratings (SRGs) in azo‐polymer films using the interference of two laser beams of appropriate polarization. However, there are few reports in the literature concerning the electro‐fabrication of SRGs on such types of polymer films. The goal of the work reported was the electro‐patterning of an azobenzene‐containing epoxy thermoplastic film. An epoxy‐based polymer functionalized with an azo‐chromophore was synthesized and characterized using thermal analysis. The reversible optical storage properties and photo‐induced dichroism were studied. SRGs were fabricated on a film of the synthesized azobenzene‐containing polymer using contact mode current‐sensing atomic force microscopy which locally applied an electric field that aligned the azobenzene moieties. The anisotropic mass transport of the azo‐polymer film was observed after applying an electric field. Additionally, the effect of the relief formation in the polymeric film surface was investigated by means of atomic force microscopy and electrostatic force microscopy. Copyright © 2010 Society of Chemical Industry

show abstract

Optical storage properties in cast films of an azopolymer

Cited by 7 publications

References 12 publications

Supramolecular order following binding of the dichroic birefringent sulfonic dye Ponceau SS to collagen fibers

Supramolecular order following binding of the dichroic birefringent sulfonic dye Ponceau SS to collagen fibers

Surface properties, thermal behavior, and molecular simulations of azo-polysiloxanes under light stimuli. Insight into the relaxation

Fabrication of surface‐relief gratings on an azobenzene‐containing epoxy‐based polymer film using atomic force microscopy

Contact Info

Product

Resources

About